The disclosed device relates to bar code scanners which are used to scan card resident bar codes for identification and other purposes in most industrialized countries. More particularly it relates to an improved method and apparatus for the faster and more accurate reading of linear and 2D bar codes which allows for progressive reading of the card when inserted into the reader thereby eliminating any aiming by the user as well as providing fast and accurate reading of the card which is read as it is pushed into the reader. The device uses a line by line approach to reading of the card as it moves laterally across the sensor. It also self aligns the card with the reading device, eliminates the need for the user to aim a reading device at the card, while concurrently alleviating the time delays caused by conventional image type readers as well as lowering power consumption and the size requirements of the card reader itself. The device also incorporates a unique method of reading such bar codes which provides for a second scan of the barcode during exit from the device wherein it will either scan the entire barcode, or scan the barcode and combine it with the first scan to find missing data from the first scan, only if needed, thereby speeding up the scanning of the bar code.
Ever prevalent in the lives of people in most industrialized countries is the use of bar codes to identify products and memorialize other information. There are typically two types of bar codes in commercial use, a linear (1D) barcode and a two dimensional (2D) barcode. A conventional 1D bar code (one dimensional UPC bar code) is just a different way of encoding numbers and letters by using a combination of bars and spaces of varying widths which in essence is just another manner of entering data into a computer. A bar code generally does not contain descriptive data. It is a reference number that a computer uses to look up an associated record that contains descriptive data and other important information. For example, a barcode found on a soda can does not contain the product name, type of soda, or price, instead, it contains a 12-digit product number. When this number is scanned by the cashier at the check-out, it is transmitted to the computer which finds the record associated with that item number in the data base. The matching item record contains a description of the product, vendor name, price, quantity-on-hand, etc. The computer instantly does a xe2x80x9cprice lookupxe2x80x9d and displays the price on the cash register. It also subtracts the quantity purchased from the quantity-on-hand. This entire transaction is done instantly. In a nutshell, a bar code typically has ID data encoded in it, and that data is used by computer to look up all specific information associated with the data.
Since computers cannot xe2x80x9creadxe2x80x9d bar codes, for a computer to make use of the information contained in the bar code, the bar code data must be captured and decoded into a data format that the computer can process. The device which reads or captures the bar code information and sends it to the decoder, is known as the bar code reader, generally called bar code scanner. A typical bar code reader kit consists of a scanner, decoder, and cable which interfaces the decoder to the computer. The Scanner scans the Bar Code symbol and captures the bars and spaces of the bar code and sends it to the decoder. The decoder translates the bars and spaces into corresponding electrical output and transmits that data to the computer in a traditional data format. A bar code scanner can either have the Decoder built into it, or have an interface between it and the computer.
The 2D barcode unlike linear codes can store the data within the code, therefore eliminating the needs for access to a database for getting the information. Large amounts of text and data can be stored securely and inexpensively. Some 2D bar codes are like a set of linear bar codes literally stacked on top of each other. Conventionally, the PDF417 is the best example of a stacked-bar symbol and is the most common of all 2D bar codes currently in use today. 2D bar codes also uses an advanced error correction instead of a check digits system. This error correction allows the symbol to withstand some physical damage without causing loss of data. This high level of error correction is far more advanced than conventional 1D linear bar codes with check digits.
Currently, four of the different types of bar code readers available include the pen type readers (bar code-wands), laser bar code scanners, CCD (Charge Couple Devices) barcode readers and camera-based barcode readers used for most two dimensional (2D) bar codes which contain much more information than standard vertical line bar codes. Each of these types uses a slightly different technology for reading and decoding a bar code.
Pen type barcode readers have a light source and a photo diode placed next to each other in the tip of a pen or wand. To read a bar code, a user drags the tip of the pen across all the bars, in a steady even motion. The photo diode measures the intensity of the light reflected back from the light source and generates a waveform corresponding to the widths of the bars and spaces in the bar code. The barcode reader sends the waveform to the decoder, which decodes the waveform and sends it to the computer in a traditional data format.
Laser barcode scanners work the same way as pen type barcode readers. The only main difference is that Laser barcode scanners use a laser beam as their light source, and typically employ either a reciprocating mirror or a rotating prism to scan the laser beam back and forth across the bar code. As with the pen type bar code reader, a photo diode is used to measure the intensity of the light reflected back from the bar code.
CCD barcode scanners use an array of tiny light sensors lined up in a row in the head of the barcode reader. Voltage waveform corresponding to the bars and spaces of the bar code is generated and sent to the decoder, which decodes the data and sends it to the computer. The main difference between a CCD barcode scanner, a pen type barcode scanner, and laser barcode scanner is that the CCD barcode scanner measures emitted ambient light from the bar code whereas pen or laser barcode scanners measure reflected light of a specific frequency originating from the scanner itself.
The camera-based barcode readers used for the majority of 2D bar codes which are becoming more popular due to increased data carrying ability, use a small video camera to capture an image of a bar code. The barcode reader then transmits that information to a computer and uses sophisticated digital image processing techniques to decode the bar code. Unfortunately this type of image processing of the entire 2D bar code is time consuming, requires the aiming of a camera to properly capture the image, consumes large amounts of computer processing and memory as well as requiring substantial electrical power to run the camera.
Linear bar codes are decoded along one axis or direction and generally encode data characters as parallel arrangements of alternating, multiple-width strips of lower reflectivity or xe2x80x9cbarsxe2x80x9d separated by absences of such strips having higher reflectivity or xe2x80x9cspaces.xe2x80x9d Each unique pattern of bars and spaces within a predetermined width defines a particular data character. A given linear symbol encodes several data characters along its length as several groups of unique bar and space patterns.
Newer data collection symbologies have departed from the typical linear symbologies to create 2D stacked or area symbologies in order to increase the amount of information encoded within a given area. Stacked symbologies or xe2x80x9cmulti-row symbologiesxe2x80x9d employ several adjacent rows of multiple-width bars and spaces. xe2x80x9cArea symbologiesxe2x80x9d or 2D matrix symbologies employ arrangements of regular polygonal data cells where the center-to-center distance of adjacent cells is uniform Reading stacked symbologies and 2D area technologies with scanning beam-type detectors typically involves a scanning approach where the beam is scanned by hand by a user with the scanner, horizontally across the large object a number of times to capture the image line by line. The user must be very careful as to the distance the card is held from the scanner or it won""t work correctly. Also, ambient light and reflections from the card surface itself can interfere with the imaging. For each sweep, the sensor output is converted to a digital signal. The digital signal is then mapped into a two-dimensional character array and processed by the computer as a whole to decode the symbol or symbols. Such line by line scanning is very time consuming, and frequently hard to accomplish as the user may shift the reader. Thus the reader will then have an incorrect indication of the relative locations of light and dark regions, thereby impairing decoding. If the card on which the bar code is resident is bent, the problems of the resulting image are increased.
To overcome such problems, two-dimensional readers have been employed that use cameras, or semiconductor or other suitable light receiving elements that image the entire two-dimensional area substantially simultaneously. This is a memory intensive operation for the processor and due to optical limitations inherent in such imaging devices. Further, these readers have a relatively small depth of field within which symbols can be read. To increase the reader""s depth of field, some two-dimensional readers employ auto focus systems which are costly and relatively slow. Moreover, even readers with auto focus systems are limited by the depth-of-field of the auto focus system. Also, bent cards with resulting bent code strips can exacerbate the reading problems. Still further, even when reading linear or stacked symbologies, such systems employ relatively complex area-type processing for finding, identifying and decoding. The complexity of such processing makes these readers undesirably slow, and large as a system, for many linear and stacked technology applications.
U.S. Pat. No. 6,193,156 (Han) is a unique card developed for reading with a presented illumination system. Here again this patent does not deal with the mechanics and operation involved with the insertion of a card into a card reader.
U.S. Pat. No. 5,569,902 (Wood) is hand-held device to read 2D code using a transparent guide for aiming employing an area sensor and unique illumination system. However, Wood requires the user to aim the device to work.
U.S. Pat. No. 4,903,815 (Hirschfield) teaches an automatic vending machine using a barcode scanner. While it mentions a switch to activate the scanner, this is a generic switching method used in any vending machine and is not designed to trigger at the cards leading edge or to help straighten the bent cards.
Finally, U.S. Pat. No. 5,886,334 (D""Entremont) instructs upon a camera-based system to capture a document for read and inspection. Here again this patent does provide any improvement with the mechanics and operation involved with the insertion of a card into a card reader and it requires a plurality of cameras to function.
As such, there exists a continuing need of improvements and simplification in the art of reading and handling coded cards while greatly increasing the capabilities in this relatively new field. Such a device should allow for the easy and fast reading of data on a 2D bar code. Such a device should require no aiming by the user to extract information from the code. Still further, such a device should aid in straightening out cards which have achieved a curved or bent surface due to long storage in a wallet or pocket. Finally, such a device should be small to allow it to be used at the point of purchase or inspection easily and should consume minimum power.
The device herein disclosed is a compact vertical insertion card scanner is a low power symbology reader, for reading one and two-dimensional bar codes. The device in the current best embodiments reads a standard A7 size card like Driver License or Credit Card without using any mechanical driver for card insertion and reading as is required by conventional line by line scanners. This is accomplished by employing a unique system that self aligns the card with the reader and lets the user insert the card into the device in a vertical or horizontal direction depending on how the barcode is disposed on the card rather than passing through in the conventional horizontal direction, and pushing the card by hand, thus eliminating the need for the conventional and time consuming mechanized drive system required of line-by line readers which must maintain registration of each line to form the digital image for the computer to decode in a time-consuming process.
In a favored embodiment the device reads the bar code employing a means of self-aligning and straitening the card for travel past an image capture device while concurrently detecting the entry of the card to turn on the reader with a switch means in the form of a micro switch. By employing a micro switch located adjacent to the entry point of the card, and inserting the card on the long side along the shorter axis, the overall height of the unit is kept to a minimum while also acting as a trigger switch to turn on the device and activate the scanner. Consequently, the device only consumes electrical power during the scanning process and may in some cases be operated with a low voltage battery. Of course the device can also be configured for insertion of the card longwise should the need arise, by making slightly taller.
As the card is inserted vertically into the device it is pressed against the scanner head by the means of a spring loaded hinged pressure plate. With the resulting close proximity of the card image to the scanner head, the image can be read faster, more accurately and with a higher resolution not encumbered by any disturbance from outside light. Also by pressing directly over the scanning area as the card is inserted, and employing a biased plate to guide the card through its lateral translation in the device, a card that retains some curvature by being carried in a person""s wallet will read the same as a flat card.
As the card reaches the lower limits of its travel having been scanned, the bottom edge of the card comes in contact with a second micro switch that turns off the device, or optionally, will reactivate the scanning device for a secondary scan of the card as it is removed from the compact vertical insertion card scanner.
In the best embodiment, a hinge engagement at the lower edge of the pressure plate allows the curved pressure heads or struts located at the top of the pressure plate, to rotate away from the card as the card is inserted, maintaining accurate alignment and constant pressure on the card. This pressure keeps the card in as close a proximity to the scanning head as possible. However, conventional embossed or raised letters on the card surface cannot affect this unique system as it passes into or out of the device with the curved struts acting as a means to prevent jamming against the surface of the pressure plate caused by the raised portions of the card.
An alternate preferred embodiment of the compact vertical insertion card scanner will incorporate a second sensor module affixed to the pressure plate maintaining the pressure against the card. The addition of a second sensor module allows for reading either one or two-dimensional bar codes on either side of the card or on both sides of the card together at the same time. With the incorporation of the two sensor units, it would not make any difference what way the card was inserted into the device and would give the device the ability to scan two data strips, to check for tampering and/or accuracy, should one of the bar codes become damaged.
Further, the provision of a second sensor module and illumination means would provide a unique ability of the device to read both the data on the bar code, and the actual photograph of the bearer which is provided on many forms of identification and credit cards. Since the barcode can be encoded with a digital photo of the bearer, and the device can acquire the actual photo of the bearer from the card, the device can also allow for either a computer comparison of the two images for a positive match, or, the projection of both the digital image from the bar code and the actual image on the card, and allow the user to view them personally, to visually ascertain if they are one and the same person. This would provide an excellent means to identify that the person presenting the card for credit or identification is the proper and authorized bearer of the card.
The preferred embodiment of the device will employ a CIS (Contact Image Scanner) type sensor such as to read the image or other indicia on the card. This sensor module employs an LED module illuminating a line uniformly as the card passes through the device. Also in the preferred embodiment is an ARM7 RISC processor, CPLD, Flash memory and memory in the form SDRAM or other conventional memory is provided to allow the card reader to process all the data on board and then interface with the computer or data processor of choice at a remote location. This miniaturizes the device even further.
By employing a Contact Image sensor (CIS) the device has a fixed Field of View (FOV) and maintains excellent Depth of Field (DOF). The CIS provides an advantage when the target bar code is less than the entire available FOV (like driver license) contacting the sensor in close proximity to the image since it can read the target faster, more accurately, and with a high resolution without any disturbance from out side light.
Further, the preferred device, by using a plurality of means for switching to signal the processor that the card has been inserted, and at the termination of insertion, that travel past the sensor module is finished, the device provides a unique method of scanning bar codes and cards which will greatly accelerate the reading of such cards. The first switching means signals the device that the card has been inserted and is translating across the sensor module. At this point power to the device is turned on thus allowing the device to remain dormant and in a power saving mode until the first switching means is activated. Once the card has fully traveled into the device and past the sensor module, it triggers a second means for switching which when activated signals the device that insertion is completed. This completion signal is sent to the communicating computer or processor and signals it to process the data from the bar code.
If at this point the computer determines that all the data from the various sections of the bar code have been adequately scanned and can be read, the device is finished and will turn off thus saving time and power. If however for some reason the computer determines that segments of data from the bar code are missing or improperly read, and the computer software cannot fully read the data, the second means for switching when moved to the open position will signal the device to run a second scan of the card during the exit travel of the card from the device and to re-scan the barcode to capture all the data again which can be processed individually if totally captured, or, combined with the first scan by the computer and software to build a total image of the bar code and thereby complete the process and read the data in the imaged bar code.
This double read rate capability allows the device to conserve power if a total image is captured on the first traverse past the sensor module, or, to continue for a second scan to capture the total image of the bar code, or as assemble a total image from both scans. Obviously the optimum method would be the capture of the total image on the first pass since both power and time are conserved. However the provision of the ability to re scan on the second pass or to assemble the image electronically using both scans adds utility and long term time savings by insuring an image is captured in one of the three manners.
It is therefor an object of this invention is to create a simple device for reading bar codes on cards whereby the card may be inserted vertically or horizontally and automatically read during insertion.
Another object of this invention is to create a device that is activated automatically when the card is inserted and turned off when the card is removed thereby saving energy and enabling batter power if desired.
An additional object of this invention is to create a device that will read a card through an automated scanning process rather than the conventional cumbersome hand held scanning device.
Another object of this invention is to create a device that will hold the card inserted as close to the sensor as possible by the means of a spring loaded, hinged pressure plate.
A still further object of this invention is the provision of a method of scanning cards inserted into the device which allows for a single scan, or if needed a dual scan to speed up processing by the communicating processor.
An additional object of this invention is the provision of a two-sided card scanning device that will scan either a plurality of bar codes on an inserted card or a photograph and a bar code on such a card and provide a comparison of both for identification of the bearer.
These together with other objects and advantages which will become subsequently apparent and reside in the details of the construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout.